face each other in denver, just two days from now. we begin tonight withnbc'sandreamitchellinour d.c. newsroom. andrea, good evening. >> good evening, brian. it is the political super bowl, or perhaps the world series. mitt romney, behind in all battleground polls for the last three weeks, now has the most to gain from a game-changing night. and the most to lose if he doesn't turn it around. as the candidates head to debate camp, rolling up their sleeves, getting down to work, each claims to be the underdog. >> governor romney, he's -- he's a good debater. i'm just okay. >> he plays, barack obama, he plays them well, too. i hate to tell you. >> reporter: mitt romney practicing with ohio senator rob portman looks like he's been getting a workout. the president sparring with john kerry, even chose a key suburb in nevada, a battleground state, for his practice session. neither candidate is known as a great debater. aides say the president doesn't like to talk in sound bites, and can be patronizing. >> you're likeable enough, hillary. >> thank you. >> reporter: romney, say advisers, ca

marker. we begin with our chief foreign affairscorrespondent,andreamitchell. >>reporter: benjamin netanyahu armed himself with a simple cartoon, to arm himself with what he says that iran has to developing a nuclear weapon. a day after iran's president mahmoud ahmadinejad from the same podium called israel uncivilized. they say that iran is close to getting ready for a nuclear bomb and has to be stopped within months. >> if these are the facts, and they are, where should a red line be drawn? a red line should be drawn right here. >> reporter: president obama told the u.n. this week he believes there is a way to avoid military action. >> america wants to resolve this issue through diplomacy, and we believe there is time and space to do so. >> the big question is, at what point can we no longer stop iran from getting the bomb? and that is why, with a red pen, he drew the line, he was showing the world the point at which we may no longer be able to stop iran from getting the weaponry. >> reporter: as netanyahu took the stage today, the president was miles away, at a campaign rally in

, that segment will be coming up in just abit.andreamitchellisheading up our team working on that. tom brokaw is another member of our team in the arena, in denver. and tom, the conventional wisdom has a way of kind of bubbling up these days during the event. and i imagine one of the plot lines tomorrow will be here's mitt romney, as we said, energized, coming right from the game. he has been in an active, very active campaign heretofore, and the president has been on the job in that realm during this whole time. >> well, governor romney did spend a lot of time preparing for this debate, and it paid off. he had a well-organized narrative. he knew his brief. and this was the candidate that the republican party's been waiting to show up, as a matter of fact. and a lot of businessmen that i've talked to that have dealt with mitt romney in the past have been bewildered by his performance as a candidate. but this is the mitt romney that they described to me as he sat down at a table and did a deal. he had a cycle of themes that he wanted to keep coming back to. the objective realities of th